For ceiling illumination and wall surface illumination, fluorescent lamps in the shape of long tubes are typically used. To make the seams between segments of linear illumination invisible, for example in indirect illumination and the like, long-tube-shaped fluorescent lamps are often arranged with their adjacent ends overlapping with one another inside a recess the inside of which is not directly visible. Proposals have also been made to improve the design of long-tube-shaped fluorescent lamps themselves to enable them to emit light even at their ends so that no seems may be visible when they are arranged linearly (Patent Document 1). On the other hand, with ever increasing use of LEDs in recent years, proposals have also been made to design white LEDs to be compatible with fluorescent lamps for use in common ceiling illumination (Patent Document 2).